309 Changes in the soluble starch component of masa associated with adhesiveness.

M. B. MIKLUS and B. R. Hamaker. Dept. of Food Science, Purdue University, West Lafayette, IN 47906-1160.

The chemical basis of masa texture is not well understood. Understanding such relationships would provide basic information on the tortilla chip and flour tortilla production process and could lead to better process control. The objective of this study was to relate a relatively low molecular weight branched, soluble starch component, that we previously identified, to masa texture. Masa from corn grown in 1996 and 1997 (IL 96 and IL 97), was made by cooking in lime [Ca(OH)(2)] solution (1% w/w) for 2, 4, 14, and 24 min, steeping for 16 hr, followed by rinsing and stone-milling. A compression-tension test using a Universal Testing Machine measured masa texture. Masa adhesiveness correlated significantly with masa moisture (r = 0.699, P > 0.05). Water soluble carbohydrate containing branched, water-soluble starch fraction of molecular weight lower than amylopectin, was extracted from masa and separated using HPLC-SEC. This system utilized a HPLC pump and SEC column packed with Sephacryl S 500 HR connected to a refractive index detector. Peak area of this fraction increased with cook time and was found to correlate significantly with adhesiveness (r = 0.822, P > 0.001). This branched, low molecular weight soluble component could be a potential indicator and causal factor of masa adhesiveness.